Disconnecting switch



June 21, 1932. F. J. FISCHER 1,863,626

DISCONNECTING SWITCH l Filed Nov. 25, 1929 Patented June 21, 1932 UNITEDSTATES PATENT OFFICE FRANZ JOSEPH FISCHER, OF DRESDEN, GERMANY, ASSIGNORT0 THE FIRM KOC STERZEL AKTIENGESELLSCHAFT, 0F DRESDEN, GERMANYDISCONNECTING SWITCH Application led November 25, 1929, Serial No.409,678, and in Germany November 29, 1928.

My invention relates to disconnecting f l necting switches are sometimescovered with ice. It is an object of my invention to avoid theice-covering of the switch and in particular of the insulators and thecontact members by providing heating resistors within the Contactmembers or within insulators of the Aswitching device and connectedeither directly or inductively, to the high voltage line so that longconnections and particular heating.

transformers are avoided. The heating resistors may be arranged in thebase portion of a rotary insulator.

In disconnecting switches with hollow in' sulators, in the interior ofwhich graded electrical devices such as measuring transformers orgrounding inductances are arranged it is a further object of myinvention to connect the heating resistor to the low voltage winding ofthe measuring transformer or the like. In such an arrangement theheating resistor has the same potential as the winding, to which it isconnected, and need not be insulated, as are the high `voltage members.

Itis still another object of my invention to provide a shunt resistor ofhigh resistance which is connected in parallel to the heating resistorinserted in a branch line connecting the high voltage line to ground. Bythis high ohmic resistorovervoltages are transmitted directly from thehigh voltage line to ground. It is a further object of my invention toprovide switching devices in series to the eating resistor so that theresistor may be switched off in summer. In this modification of myinvention it is preferable to provide adjustable additional resistors,inductances, capacities or combinations of the same inthe secondarycircuits of the measuring transformers to preserve the accuracy and thesensibility of the measuring instruments. In the drawing affixed to thisspeciiication4 and forming part thereof several devices embodying myinvention are illustrated diagrammatically by way of example.

In the drawing:

Fig. 1 is a vertical section of a single break disconnect-ing switch ofthe rotary type, and

Fig. 2 is a similar section of a double break disconnecting switch ofthe same type.

Referring now to Fig. 1, 11 is an U-shaped iron member supportingstationary insulators 12, 13 of a rotary disconnecting switch. 14 is aball and socket joint for the rotary switching blade 15 supported by theinsulator 12. 16 is a heating resistor formed as a rod and insulatedfrom the blade 15. 17 is a removable closing member arranged at the endof the blade 15. When the member 17 is removed, the resistor 16 may beput in place in the blade 15. The terminals of the resistor 16 areconnected to the closing member 17 and to a contact plug 18 respectivelyconnected to a resistor 19 arranged within the hollow insulator 12. Theresistor 19 is connected to ground and by means of the high ohmicresistor 20 to the blade 15, so that the heating resistor is shunted bythe high ohmic resistor 20. 21 is a stationary contact member supportedby the insulator 13, and engaged by the extension 15 of the blade 15 inthe closed position 4of the switch.

The operation of the device is as follows: When the switch is in itsclosed position, the heat produced in-the resistor 16 is transmitted byconductivity to the ball and socket joint 14, the switching blade 15 andthe stationary contact member 21. In consequence thereof these parts arenot covered with ice even at low temperatures. Snow falling on thedisconnecting blade 15 is melted by the heat produced in the resistor 16so that mechanical overloads of the disconnecting blades are avoided. Insummer the heating resistor 16 may be taken out from the blade 15 afterremoving the closing member 17.

Referring to Fig. 2, 24 and 26 are the stationary insulators and 25 therotatable insulator of a high voltage disconnecting switch ofthe rotortype. 22 and 23 are the stationary contacts supported by the stationaryinsulators 24 land 26, respectively. The movable insulator 25 issupported by means of a ball bearing 27. 28, 29 and 30 are gradedvoltage and current transformers and a grounding inductance, arrangedwithin the hollow insulators 24, 25 and 26, respectively. 3l is aheating resistor arranged within the stationary contact member 22 andconnected to the first primary winding of the voltage transformer 28. 32is an adjustable resistor shortcircuited by the switch 33, when theheating resistance 3l is inserted. When the heating resistance 3l isremoved, the switch 33 Yis opened so that the accuracy and sensibilityof the voltmeter 42 is preserved. It an increase of the heating eect isdesired, an additional resistor (not shown) of low resistance may beinserted in parallel to the measuring instrument by means of a pushbutton switch (not shown) or the like.

The base portion 34 of the movable insulator 25 is heated by means ofthe heating resistor 35, the latter being connected to the lowestcurrent transformer 29 by means of a heating winding 36. The heatingresistor 35 may be switched oii` by opening the switch 37. Instead ofthis the heating resistor 35 may be arranged replaceably by means ofplug contacts or the like. The heating resistor may be arranged in thestationary supporting portion instead of within the movable baseportion, iiexible connections such as the connections 38 of the ammeter43 or sliding contacts being then provided between the winding 36 andthe heating resistor 35. 23 is a stationary contact member supported bythe insulator 26 and heated by the heating resistor 39 connected to theterminal of the graded grounding inductance 30. The resistor 39 isshunted by the high ohmic resistor 44 arranged within the head cover 40of the insulator 26.

4l is the movable disconnecting blade. Heating resistors (not shown) maybe arranged within the blade 41. in the manner shown in Fig. l. When itis desired to heat the resistor 35 even when the blade 41 is in its openposition, the heating resistor 35 may be connected to a supplementarywinding or to taps of any living parts ofthe system (not shown). Theinsulators and insulating casings are heated by the heat produced in thedevices (measuring transformers, grounding inductances or the like)arranged within the hollow insulators. Hereby the effect of the heat-ingresistor is accentuated. The connecting lines are arranged in theinterior of the insulators and need not be shielded aga-inst electricalradiation.

I wish it to be understood, that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

In the claims afliXed to this speciiication no selection ot' anyparticular modiiication of the invention is intended to the exclusion ofother modifications thereof and the right to subsequently make claims toany modification not covered by these claims is expressly reserved.

aaeaeae I claim:

l. A. high voltage disconnecting switch comprising a hollow insulator, alive member and a heating resistance both supported by said insulatorand thermally connected to each other, one end of said heatingresistance being electrically connected to said live member, and animpedance within said insulator having its ends electrically connectedto the other end of said heat-ing resistance and to ground respectively.

2. A high voltage disconnecting switch comprising a hollow insulator, aswitching member and a heating resistance both supported by saidinsulator and thermally con nected to each other, one end of saidheating resistance bein electrically connected to said switching mem r,and an impedance within said insulator having its ends electricallyconnected to the other end of said heating resistance and to groundrespectively.

3. A high voltage disconnecting switch comprising a hollow insulator, amovable contact member and a heating resistance both supported by saidinsulator and thermally connected to each other, one end of said heat-.ing resistance being electrically connected to said movable contactmember and an impedance within said insulator having its endselectrically connected to the other end of said heating resistance andto ground respectively.

4. A high voltage disconnecting switch comprising a hollow insulator, ahollow dis connecting blade supported by said insulator and a heatingresistance formed as a rod and exchangeably arranged within saiddisconnecting blade, one end of said heating resistance beingelectrically connected to said disconnecting blade and an impedancewithin said insulator having its ends electrically connected to theother end of said heating resistance and to ground respectively.

5. A high voltage disconnecting switch comprising a hollow insulator, ahollow disconnecting blade supported by said insulator and a heatingresistance formed as a rod and exchangeably arranged within saiddisconneeting blade, one end of said heating're sistance beingelectrically connected to said disconnecting blade, a high ohmicresistor connected in parallel to said heating resistance and animpedance within said insulator having its ends electrically connectedto the other end of said heating resistance and to ground respectively.

6. A high voltage disconnecting switch comprising a hollow insulator, alive'imember and a heating resistance both supported by said insulatorand thermally connected to each other, one end of said heatingresistance being electrically connected to said live member, a voltagetransformer winding within said insulator having its ends electricallyconnected to said live member and to ground respectively, and a tap insaid transformer said insulator and thermally connected to eachother,one end of said heating resistance being electrically connected to saidlive member,`aset 'of voltage transformer windings connected in serieswithin said insulator, the ends of said set being electrically connectedto said live member and to ground respectively, and a tap in theuppermost of said transformer windings being electrically connected tothe other end of said heating resistance.

8. 'A high voltage disconnecting switch comprising a hollow insulator, alive member and a heating resistance both supported by said insulatorand thermally connected to each other, one end of said heatingresistance being electrically connected to said live member, and agraded impedance within said insulator having its ends electricallyconnected to the other end of said heating resistance and to groundrespectively.

In testimony whereof I affix my signature.

FRANZ JOSEPH FISCHER.

